source: lib/misc.c @ df67b48

/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/*
 * Various utility functions. Some are copied from Gaim to support the
 * IM-modules, most are from BitlBee.
 *
 * Copyright (C) 1998-1999, Mark Spencer <markster@marko.net>
 *                          (and possibly other members of the Gaim team)
 * Copyright 2002-2012 Wilmer van der Gaast <wilmer@gaast.net>
 */

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#define BITLBEE_CORE
#include "nogaim.h"
#include "base64.h"
#include "md5.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <glib.h>
#include <time.h>

#ifdef HAVE_RESOLV_A
#include <arpa/nameser.h>
#include <resolv.h>
#endif

#include "md5.h"
#include "ssl_client.h"

void strip_linefeed(gchar *text)
{
        int i, j;
        gchar *text2 = g_malloc(strlen(text) + 1);

        for (i = 0, j = 0; text[i]; i++) {
                if (text[i] != '\r') {
                        text2[j++] = text[i];
                }
        }
        text2[j] = '\0';

        strcpy(text, text2);
        g_free(text2);
}

time_t get_time(int year, int month, int day, int hour, int min, int sec)
{
        struct tm tm;

        memset(&tm, 0, sizeof(struct tm));
        tm.tm_year = year - 1900;
        tm.tm_mon = month - 1;
        tm.tm_mday = day;
        tm.tm_hour = hour;
        tm.tm_min = min;
        tm.tm_sec = sec >= 0 ? sec : time(NULL) % 60;

        return mktime(&tm);
}

time_t mktime_utc(struct tm *tp)
{
        struct tm utc;
        time_t res, tres;

        tp->tm_isdst = -1;
        res = mktime(tp);
        /* Problem is, mktime() just gave us the GMT timestamp for the
           given local time... While the given time WAS NOT local. So
           we should fix this now.

           Now I could choose between messing with environment variables
           (kludgy) or using timegm() (not portable)... Or doing the
           following, which I actually prefer...

           tzset() may also work but in other places I actually want to
           use local time.

           FFFFFFFFFFFFFFFFFFFFFUUUUUUUUUUUUUUUUUUUU!! */
        gmtime_r(&res, &utc);
        utc.tm_isdst = -1;
        if (utc.tm_hour == tp->tm_hour && utc.tm_min == tp->tm_min) {
                /* Sweet! We're in UTC right now... */
                return res;
        }

        tres = mktime(&utc);
        res += res - tres;

        /* Yes, this is a hack. And it will go wrong around DST changes.
           BUT this is more likely to be threadsafe than messing with
           environment variables, and possibly more portable... */

        return res;
}

typedef struct htmlentity {
        char code[7];
        char is[3];
} htmlentity_t;

static const htmlentity_t ent[] =
{
        { "lt",     "<" },
        { "gt",     ">" },
        { "amp",    "&" },
        { "apos",   "'" },
        { "quot",   "\"" },
        { "aacute", "á" },
        { "eacute", "é" },
        { "iacute", "é" },
        { "oacute", "ó" },
        { "uacute", "ú" },
        { "agrave", "à" },
        { "egrave", "è" },
        { "igrave", "ì" },
        { "ograve", "ò" },
        { "ugrave", "ù" },
        { "acirc",  "â" },
        { "ecirc",  "ê" },
        { "icirc",  "î" },
        { "ocirc",  "ô" },
        { "ucirc",  "û" },
        { "auml",   "ä" },
        { "euml",   "ë" },
        { "iuml",   "ï" },
        { "ouml",   "ö" },
        { "uuml",   "ü" },
        { "nbsp",   " " },
        { "",        ""  }
};

void strip_html(char *in)
{
        char *start = in;
        char out[strlen(in) + 1];
        char *s = out, *cs;
        int i, matched;
        int taglen;

        memset(out, 0, sizeof(out));

        while (*in) {
                if (*in == '<' && (g_ascii_isalpha(*(in + 1)) || *(in + 1) == '/')) {
                        /* If in points at a < and in+1 points at a letter or a slash, this is probably
                           a HTML-tag. Try to find a closing > and continue there. If the > can't be
                           found, assume that it wasn't a HTML-tag after all. */

                        cs = in;

                        while (*in && *in != '>') {
                                in++;
                        }

                        taglen = in - cs - 1;   /* not <0 because the above loop runs at least once */
                        if (*in) {
                                if (g_strncasecmp(cs + 1, "b", taglen) == 0) {
                                        *(s++) = '\x02';
                                } else if (g_strncasecmp(cs + 1, "/b", taglen) == 0) {
                                        *(s++) = '\x02';
                                } else if (g_strncasecmp(cs + 1, "i", taglen) == 0) {
                                        *(s++) = '\x1f';
                                } else if (g_strncasecmp(cs + 1, "/i", taglen) == 0) {
                                        *(s++) = '\x1f';
                                } else if (g_strncasecmp(cs + 1, "br", taglen) == 0) {
                                        *(s++) = '\n';
                                } else if (g_strncasecmp(cs + 1, "br/", taglen) == 0) {
                                        *(s++) = '\n';
                                } else if (g_strncasecmp(cs + 1, "br /", taglen) == 0) {
                                        *(s++) = '\n';
                                }
                                in++;
                        } else {
                                in = cs;
                                *(s++) = *(in++);
                        }
                } else if (*in == '&') {
                        cs = ++in;
                        while (*in && g_ascii_isalpha(*in)) {
                                in++;
                        }

                        if (*in == ';') {
                                in++;
                        }
                        matched = 0;

                        for (i = 0; *ent[i].code; i++) {
                                if (g_strncasecmp(ent[i].code, cs, strlen(ent[i].code)) == 0) {
                                        int j;

                                        for (j = 0; ent[i].is[j]; j++) {
                                                *(s++) = ent[i].is[j];
                                        }

                                        matched = 1;
                                        break;
                                }
                        }

                        /* None of the entities were matched, so return the string */
                        if (!matched) {
                                in = cs - 1;
                                *(s++) = *(in++);
                        }
                } else {
                        *(s++) = *(in++);
                }
        }

        strcpy(start, out);
}

char *escape_html(const char *html)
{
        const char *c = html;
        GString *ret;
        char *str;

        if (html == NULL) {
                return(NULL);
        }

        ret = g_string_new("");

        while (*c) {
                switch (*c) {
                case '&':
                        ret = g_string_append(ret, "&amp;");
                        break;
                case '<':
                        ret = g_string_append(ret, "&lt;");
                        break;
                case '>':
                        ret = g_string_append(ret, "&gt;");
                        break;
                case '"':
                        ret = g_string_append(ret, "&quot;");
                        break;
                default:
                        ret = g_string_append_c(ret, *c);
                }
                c++;
        }

        str = ret->str;
        g_string_free(ret, FALSE);
        return(str);
}

/* Decode%20a%20file%20name                                             */
void http_decode(char *s)
{
        char *t;
        int i, j, k;

        t = g_new(char, strlen(s) + 1);

        for (i = j = 0; s[i]; i++, j++) {
                if (s[i] == '%') {
                        if (sscanf(s + i + 1, "%2x", &k)) {
                                t[j] = k;
                                i += 2;
                        } else {
                                *t = 0;
                                break;
                        }
                } else {
                        t[j] = s[i];
                }
        }
        t[j] = 0;

        strcpy(s, t);
        g_free(t);
}

/* Warning: This one explodes the string. Worst-cases can make the string 3x its original size! */
/* This function is safe, but make sure you call it safely as well! */
void http_encode(char *s)
{
        char t[strlen(s) + 1];
        int i, j;

        strcpy(t, s);
        for (i = j = 0; t[i]; i++, j++) {
                /* Warning: g_ascii_isalnum() is locale-aware, so don't use it here! */
                if ((t[i] >= 'A' && t[i] <= 'Z') ||
                    (t[i] >= 'a' && t[i] <= 'z') ||
                    (t[i] >= '0' && t[i] <= '9') ||
                    strchr("._-~", t[i])) {
                        s[j] = t[i];
                } else {
                        sprintf(s + j, "%%%02X", ((unsigned char *) t)[i]);
                        j += 2;
                }
        }
        s[j] = 0;
}

/* Strip newlines from a string. Modifies the string passed to it. */
char *strip_newlines(char *source)
{
        int i;

        for (i = 0; source[i] != '\0'; i++) {
                if (source[i] == '\n' || source[i] == '\r') {
                        source[i] = ' ';
                }
        }

        return source;
}

/* Wrap an IPv4 address into IPv6 space. Not thread-safe... */
char *ipv6_wrap(char *src)
{
        static char dst[64];
        int i;

        for (i = 0; src[i]; i++) {
                if ((src[i] < '0' || src[i] > '9') && src[i] != '.') {
                        break;
                }
        }

        /* Hmm, it's not even an IP... */
        if (src[i]) {
                return src;
        }

        g_snprintf(dst, sizeof(dst), "::ffff:%s", src);

        return dst;
}

/* Unwrap an IPv4 address into IPv6 space. Thread-safe, because it's very simple. :-) */
char *ipv6_unwrap(char *src)
{
        int i;

        if (g_strncasecmp(src, "::ffff:", 7) != 0) {
                return src;
        }

        for (i = 7; src[i]; i++) {
                if ((src[i] < '0' || src[i] > '9') && src[i] != '.') {
                        break;
                }
        }

        /* Hmm, it's not even an IP... */
        if (src[i]) {
                return src;
        }

        return (src + 7);
}

/* Convert from one charset to another.

   from_cs, to_cs: Source and destination charsets
   src, dst: Source and destination strings
   size: Size if src. 0 == use strlen(). strlen() is not reliable for UNICODE/UTF16 strings though.
   maxbuf: Maximum number of bytes to write to dst

   Returns the number of bytes written to maxbuf or -1 on an error.
*/
signed int do_iconv(char *from_cs, char *to_cs, char *src, char *dst, size_t size, size_t maxbuf)
{
        GIConv cd;
        size_t res;
        size_t inbytesleft, outbytesleft;
        char *inbuf = src;
        char *outbuf = dst;

        cd = g_iconv_open(to_cs, from_cs);
        if (cd == (GIConv) - 1) {
                return -1;
        }

        inbytesleft = size ? size : strlen(src);
        outbytesleft = maxbuf - 1;
        res = g_iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
        *outbuf = '\0';
        g_iconv_close(cd);

        if (res != 0) {
                return -1;
        } else {
                return outbuf - dst;
        }
}

/* A wrapper for /dev/urandom.
 * If /dev/urandom is not present or not usable, it calls abort()
 * to prevent bitlbee from working without a decent entropy source */
void random_bytes(unsigned char *buf, int count)
{
        int fd;

        if (((fd = open("/dev/urandom", O_RDONLY)) == -1) ||
            (read(fd, buf, count) == -1)) {
                log_message(LOGLVL_ERROR, "/dev/urandom not present - aborting");
                abort();
        }

        close(fd);
}

int is_bool(char *value)
{
        if (*value == 0) {
                return 0;
        }

        if ((g_strcasecmp(value,
                          "true") == 0) || (g_strcasecmp(value, "yes") == 0) || (g_strcasecmp(value, "on") == 0)) {
                return 1;
        }
        if ((g_strcasecmp(value,
                          "false") == 0) || (g_strcasecmp(value, "no") == 0) || (g_strcasecmp(value, "off") == 0)) {
                return 1;
        }

        while (*value) {
                if (!g_ascii_isdigit(*value)) {
                        return 0;
                } else {
                        value++;
                }
        }

        return 1;
}

int bool2int(char *value)
{
        int i;

        if ((g_strcasecmp(value,
                          "true") == 0) || (g_strcasecmp(value, "yes") == 0) || (g_strcasecmp(value, "on") == 0)) {
                return 1;
        }
        if ((g_strcasecmp(value,
                          "false") == 0) || (g_strcasecmp(value, "no") == 0) || (g_strcasecmp(value, "off") == 0)) {
                return 0;
        }

        if (sscanf(value, "%d", &i) == 1) {
                return i;
        }

        return 0;
}

struct ns_srv_reply **srv_lookup(char *service, char *protocol, char *domain)
{
        struct ns_srv_reply **replies = NULL;

#ifdef HAVE_RESOLV_A
        struct ns_srv_reply *reply = NULL;
        char name[1024];
        unsigned char querybuf[1024];
        const unsigned char *buf;
        ns_msg nsh;
        ns_rr rr;
        int n, len, size;

        g_snprintf(name, sizeof(name), "_%s._%s.%s", service, protocol, domain);

        if ((size = res_query(name, ns_c_in, ns_t_srv, querybuf, sizeof(querybuf))) <= 0) {
                return NULL;
        }

        if (ns_initparse(querybuf, size, &nsh) != 0) {
                return NULL;
        }

        n = 0;
        while (ns_parserr(&nsh, ns_s_an, n, &rr) == 0) {
                char name[NS_MAXDNAME];

                if (ns_rr_rdlen(rr) < 7) {
                        break;
                }

                buf = ns_rr_rdata(rr);

                if (dn_expand(querybuf, querybuf + size, &buf[6], name, NS_MAXDNAME) == -1) {
                        break;
                }

                len = strlen(name) + 1;

                reply = g_malloc(sizeof(struct ns_srv_reply) + len);
                memcpy(reply->name, name, len);

                reply->prio = (buf[0] << 8) | buf[1];
                reply->weight = (buf[2] << 8) | buf[3];
                reply->port = (buf[4] << 8) | buf[5];

                n++;
                replies = g_renew(struct ns_srv_reply *, replies, n + 1);
                replies[n - 1] = reply;
        }
        if (replies) {
                replies[n] = NULL;
        }
#endif

        return replies;
}

void srv_free(struct ns_srv_reply **srv)
{
        int i;

        if (srv == NULL) {
                return;
        }

        for (i = 0; srv[i]; i++) {
                g_free(srv[i]);
        }
        g_free(srv);
}

/* From OpenSSH 7.4p1 canohost.c" */
char *reverse_lookup(const struct sockaddr *from_, const socklen_t fromlen_)
{
        struct sockaddr_storage from;
        socklen_t fromlen;
        struct addrinfo hints, *ai, *aitop;
        char name[NI_MAXHOST], ntop2[NI_MAXHOST];
        char ntop[INET6_ADDRSTRLEN];

        fromlen = sizeof(from);
        memset(&from, 0, sizeof(from));
        memcpy(&from, from_, fromlen_);
        ipv64_normalise_mapped(&from, &fromlen);
        if (from.ss_family == AF_INET6) {
                fromlen = sizeof(struct sockaddr_in6);
        }

        if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop),
            NULL, 0, NI_NUMERICHOST) != 0) {
                return NULL;
        }

        /* Map the IP address to a host name. */
        if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
            NULL, 0, NI_NAMEREQD) != 0) {
                /* Host name not found.  Use ip address. */
                return g_strdup(ntop);
        }

        /*
         * if reverse lookup result looks like a numeric hostname,
         * someone is trying to trick us by PTR record like following:
         *      1.1.1.10.in-addr.arpa.  IN PTR  2.3.4.5
         */
        memset(&hints, 0, sizeof(hints));
        hints.ai_socktype = SOCK_DGRAM; /*dummy*/
        hints.ai_flags = AI_NUMERICHOST;
        if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
                freeaddrinfo(ai);
                return g_strdup(ntop);
        }

        /* Names are stored in lowercase. */
        char *tolower = g_utf8_strdown(name, -1);
        g_snprintf(name, sizeof(name), "%s", tolower);
        g_free(tolower);

        /*
         * Map it back to an IP address and check that the given
         * address actually is an address of this host.  This is
         * necessary because anyone with access to a name server can
         * define arbitrary names for an IP address. Mapping from
         * name to IP address can be trusted better (but can still be
         * fooled if the intruder has access to the name server of
         * the domain).
         */
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = from.ss_family;
        hints.ai_socktype = SOCK_STREAM;
        if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
                return g_strdup(ntop);
        }
        /* Look for the address from the list of addresses. */
        for (ai = aitop; ai; ai = ai->ai_next) {
                if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
                    sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
                    (strcmp(ntop, ntop2) == 0))
                        break;
        }
        freeaddrinfo(aitop);
        /* If we reached the end of the list, the address was not there. */
        if (ai == NULL) {
                /* Address not found for the host name. */
                return g_strdup(ntop);
        }
        return g_strdup(name);
}

void
ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
{
        struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr;
        struct sockaddr_in *a4 = (struct sockaddr_in *)addr;
        struct in_addr inaddr;
        u_int16_t port;

        if (addr->ss_family != AF_INET6 ||
            !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))
                return;

        memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));
        port = a6->sin6_port;

        memset(a4, 0, sizeof(*a4));

        a4->sin_family = AF_INET;
        *len = sizeof(*a4);
        memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr));
        a4->sin_port = port;
}

char *word_wrap(const char *msg, int line_len)
{
        GString *ret = g_string_sized_new(strlen(msg) + 16);

        while (strlen(msg) > line_len) {
                int i;

                /* First try to find out if there's a newline already. Don't
                   want to add more splits than necessary. */
                for (i = line_len; i > 0 && msg[i] != '\n'; i--) {
                        ;
                }
                if (msg[i] == '\n') {
                        g_string_append_len(ret, msg, i + 1);
                        msg += i + 1;
                        continue;
                }

                for (i = line_len; i > 0; i--) {
                        if (msg[i] == '-') {
                                g_string_append_len(ret, msg, i + 1);
                                g_string_append_c(ret, '\n');
                                msg += i + 1;
                                break;
                        } else if (msg[i] == ' ') {
                                g_string_append_len(ret, msg, i);
                                g_string_append_c(ret, '\n');
                                msg += i + 1;
                                break;
                        }
                }
                if (i == 0) {
                        const char *end;
                        size_t len;

                        g_utf8_validate(msg, line_len, &end);

                        len = (end != msg) ? end - msg : line_len;

                        g_string_append_len(ret, msg, len);
                        g_string_append_c(ret, '\n');
                        msg += len;
                }
        }
        g_string_append(ret, msg);

        return g_string_free(ret, FALSE);
}

gboolean ssl_sockerr_again(void *ssl)
{
        if (ssl) {
                return ssl_errno == SSL_AGAIN;
        } else {
                return sockerr_again();
        }
}

/* Returns values: -1 == Failure (base64-decoded to something unexpected)
                    0 == Okay
                    1 == Password doesn't match the hash. */
int md5_verify_password(char *password, char *hash)
{
        md5_byte_t *pass_dec = NULL;
        md5_byte_t pass_md5[16];
        md5_state_t md5_state;
        int ret = -1, i;

        if (base64_decode(hash, &pass_dec) == 21) {
                md5_init(&md5_state);
                md5_append(&md5_state, (md5_byte_t *) password, strlen(password));
                md5_append(&md5_state, (md5_byte_t *) pass_dec + 16, 5);  /* Hmmm, salt! */
                md5_finish(&md5_state, pass_md5);

                for (i = 0; i < 16; i++) {
                        if (pass_dec[i] != pass_md5[i]) {
                                ret = 1;
                                break;
                        }
                }

                /* If we reached the end of the loop, it was a match! */
                if (i == 16) {
                        ret = 0;
                }
        }

        g_free(pass_dec);

        return ret;
}

/* Split commands (root-style, *not* IRC-style). Handles "quoting of"
   white\ space in 'various ways'. Returns a NULL-terminated static
   char** so watch out with nested use! Definitely not thread-safe. */
char **split_command_parts(char *command, int limit)
{
        static char *cmd[IRC_MAX_ARGS + 1];
        char *s, q = 0;
        int k;

        memset(cmd, 0, sizeof(cmd));
        cmd[0] = command;
        k = 1;
        for (s = command; *s && k < IRC_MAX_ARGS; s++) {
                if (*s == ' ' && !q) {
                        *s = 0;
                        while (*++s == ' ') {
                                ;
                        }
                        if (k != limit && (*s == '"' || *s == '\'')) {
                                q = *s;
                                s++;
                        }
                        if (*s) {
                                cmd[k++] = s;
                                if (limit && k > limit) {
                                        break;
                                }
                                s--;
                        } else {
                                break;
                        }
                } else if (*s == '\\' && ((!q && s[1]) || (q && q == s[1]))) {
                        char *cpy;

                        for (cpy = s; *cpy; cpy++) {
                                cpy[0] = cpy[1];
                        }
                } else if (*s == q) {
                        q = *s = 0;
                }
        }

        /* Full zero-padding for easier argc checking. */
        while (k <= IRC_MAX_ARGS) {
                cmd[k++] = NULL;
        }

        return cmd;
}

char *get_rfc822_header(const char *text, const char *header, int len)
{
        int hlen = strlen(header), i;
        const char *ret;

        if (text == NULL) {
                return NULL;
        }

        if (len == 0) {
                len = strlen(text);
        }

        i = 0;
        while ((i + hlen) < len) {
                /* Maybe this is a bit over-commented, but I just hate this part... */
                if (g_strncasecmp(text + i, header, hlen) == 0) {
                        /* Skip to the (probable) end of the header */
                        i += hlen;

                        /* Find the first non-[: \t] character */
                        while (i < len && (text[i] == ':' || text[i] == ' ' || text[i] == '\t')) {
                                i++;
                        }

                        /* Make sure we're still inside the string */
                        if (i >= len) {
                                return(NULL);
                        }

                        /* Save the position */
                        ret = text + i;

                        /* Search for the end of this line */
                        while (i < len && text[i] != '\r' && text[i] != '\n') {
                                i++;
                        }

                        /* Copy the found data */
                        return(g_strndup(ret, text + i - ret));
                }

                /* This wasn't the header we were looking for, skip to the next line. */
                while (i < len && (text[i] != '\r' && text[i] != '\n')) {
                        i++;
                }
                while (i < len && (text[i] == '\r' || text[i] == '\n')) {
                        i++;
                }

                /* End of headers? */
                if ((i >= 4 && strncmp(text + i - 4, "\r\n\r\n", 4) == 0) ||
                    (i >= 2 && (strncmp(text + i - 2, "\n\n", 2) == 0 ||
                                strncmp(text + i - 2, "\r\r", 2) == 0))) {
                        break;
                }
        }

        return NULL;
}

/* Takes a string, truncates it where it's safe, returns the new length */
int truncate_utf8(char *string, int maxlen)
{
        char *end;

        g_utf8_validate((const gchar *) string, maxlen, (const gchar **) &end);
        *end = '\0';
        return end - string;
}

/* Parses a guint64 from string, returns TRUE on success */
gboolean parse_int64(char *string, int base, guint64 *number)
{
        guint64 parsed;
        char *endptr;

        errno = 0;
        parsed = g_ascii_strtoull(string, &endptr, base);
        if (errno || endptr == string || *endptr != '\0') {
                return FALSE;
        }
        *number = parsed;
        return TRUE;
}

/* Filters all the characters in 'blacklist' replacing them with 'replacement'.
 * Modifies the string in-place and returns the string itself.
 * For the opposite, use g_strcanon() */
char *str_reject_chars(char *string, const char *reject, char replacement)
{
        char *c = string;

        while (*c) {
                c += strcspn(c, reject);
                if (*c) {
                        *c = replacement;
                }
        }

        return string;
}

/* Returns a string that is exactly 'char_len' utf8 characters long (not bytes),
 * padded to the right with spaces or truncated with the 'ellipsis' parameter
 * if specified (can be NULL).
 * Returns a newly allocated string, or NULL on invalid parameters. */
char *str_pad_and_truncate(const char *string, long char_len, const char *ellipsis)
{
        size_t string_len = strlen(string);
        size_t ellipsis_len = (ellipsis) ? strlen(ellipsis) : 0;
        long orig_len = g_utf8_strlen(string, -1);

        g_return_val_if_fail(char_len > ellipsis_len, NULL);

        if (orig_len > char_len) {
                char *ret = g_malloc(string_len + 1);
                g_utf8_strncpy(ret, string, char_len - ellipsis_len);
                if (ellipsis) {
                        g_strlcat(ret, ellipsis, string_len);
                }
                return ret;
        } else if (orig_len < char_len) {
                return g_strdup_printf("%s%*s", string, (int) (char_len - orig_len), "");
        } else {
                return g_strdup(string);
        }
}